1. Field of the Invention
This invention generally relates to air filtration systems, and more particularly to a system and method for removing contaminates and other particulate matter from the air in a mail sorting room. The invention has particular application to reducing cross-contamination caused by a letter laced with anthrax or another harmful biological substance.
2. Description of the Related Art
Mail security has more than ever before become a vital national security interest. For the first time in our nation's history, the mail has been used as a vehicle of terrorism both by domestic and foreign enemies. The World Trade Center tragedy made every American painfully aware of the scope of destruction a determined terrorist could exact. This tragedy resulted in the loss of more than six thousand lives in the two most prominent cities of this nation, and is generally considered to be the defining event which marked a new age in terrorism.
While these cataclysmic acts have left their emotional mark on the American psyche to be sure, an evil far greater than suicide highjackers serves as the most serious threat today. This evil has the potential of operating as a silent killer and of taking far more lives than most wars. In fact, experts acknowledge that bioterrorism, if exacted in epidemic proportions, can result in a loss of life measurable in the tens or even hundreds of thousands.
In our most recent experiences with terrorism, what was once thought of as an unlikely threat became a grim reality. Letters addressed to prominent media figures and public officials were sent through the mail laced with anthrax. This resulted in infecting not only the staff of the intended recipients but also members of their families. Perhaps even more shockingly, many post office employees who carried and sorted the unopened letters also contracted and died from the disease.
In at least two cases, anthrax infection resulted from cross-contamination, a phenomenon which occurs, for example, when anthrax spores migrate from one letter to another letter or person. Authorities have determined that this could happen when the anthrax-contaminated letter comes into physical contact with another letter or when the spores become airborne and susceptible to inhalation.
A number of approaches have been proposed for dealing with anthrax exposure and other bio-terrorist acts perpetrated through the mail. One approach involves equipping mail sorting personnel with gloves and masks designed to protect against airborne particulates. This approach has often proven to be ineffective for protecting the facility. If small enough, anthrax spores will become suspended in the air for long periods of time. This makes them exceptionally difficult to protect against. For example, any patch of exposed skin could become infected even if gloves and a mask are worn. The spores could also attach themselves to the workers clothes, which could result in infecting anyone coming into contact with them.
Another approach involves irradiating the mail at some point prior to delivery. While this may prove to be effective in a certain percentage of cases, there is no guarantee that irradiation will kill all of the biological contaminates associated with a given letter. Irradiation does not solve the problem of contamination or cross-contamination resulting from airborne anthrax spores one-hundred percent of the time. Furthermore, security issues exist from the irradiation unit to the end-user or client.
In view of the foregoing considerations, it is clear that there is a critical need for an improved system and method of protecting mail-sorting personnel and facilities from biological contamination, and moreover one which is especially effective in preventing infection resulting from cross-contamination.